As you can see in the example below, the drawing gets its character from the roughness of its lines. You would not want to lose the distinctness of the line during the vectorization process.

The options in this style force two passes of the vectorization process to apply different values to the line art and colour art (-2pass). You must specify values for the line art and colour art when you use this option.

For drawings with specific vector-style lines or mattes, you only need one pass. For greyscale drawings, you may want to pass through the vectorization process twice to apply different values to the line art and colour art.

The colour art (-threshc) and line art (-threshl) thresholds determine what values in the scanned image will be considered as part of the drawing, and what will be ignored and eliminated in the vectorized drawing. Zero (0) is white and one (1) is black. The threshold is between these two values.

The expand_bitmap and jag_filter options work together so that you can pick up noise, or small pencil lines and marks, during the vectorization process. The expand_bitmap option expands the bitmap to pick up the noise. When used with jag_filter, the bitmap is shrunk down by the value of the option. You use these two options together to maintain the size of your line art.

The fit_error options smooth ink lines and colour art strokes.

The rmv_holes and rmv_dirt options remove hair and dirt of a specific size from the line art and colour art. The rmv_hairs option removes tiny strokes that extend from main colour art strokes. And, rmv_triangles option removes triangles and intersections that are less than the specified distance apart.

Greyscale soft edge

Use this vectorize style when you want to create a vector image with fine, textured strokes. Unlike the Grayscale rougher lines style, this style is meant for more subtle line variations.

Compare these options to the Grayscale rougher lines style. You will notice that the -thresh values are smaller; therefore, fewer pixels will be filtered out.This contributes to the fluffier appearance of the lines. You will also notice that the fit_error value is smaller and the -expand_bitmap value is larger. All of these options contribute to the smoother appearance of the final line.